The present invention relates to a method of washing and more particularly to a method of washing for removal of oil-type stains from fabrics.
The persistence of oil-type stains is a well recognized problem and a variety of approaches for reducing such stains to a minimum have been proposed. One commercially available approach for treating oily stains has been that of spraying certain high-foaming surfactants together with a solvent onto the soiled fabric. Commercially available products of this type include Prep.sup..TM., Spray N'Wash.sup..TM., and Shout.sup..TM.. Although such products may well be effective in removing oily stains, they are labor intensive when utilized. This is a problem with respect to large amounts of laundry having many soiled areas.
Another approach has been use of the presoak products which may include enzymes or high-foaming surfactants such as linear alkyl benzene sulfonates, alkyl ether sulfonates and the like. Such products require an extended soaking period and are therefore not completely satisfactory particularly for use in institutional laundries where high throughput is important.
A further approach has been to include highly alkaline materials as a prewash to remove loose soil materials. The highly alkaline materials do not adequately remove oily soils.